More Constraints On Primordial Black Holes

A new study, that doesn't rely on the micro-lensing and Hawking radiation exclusions which are the primary methods for constraining primordial black hole frequency, places very strict limitations on the maximum potential abundance of "supermassive" primordial black holes. 

It limits them to less than 0.1% of dark matter in a dark matter particle hypothesis for "supermassive" primordial black holes (i.e. primordial black holes that are 10,000 times more massive than the Sun or more). This had already been ruled out long ago, albeit not quite so strictly. 

The main focus on primordial black holes as a dark matter candidate has been on asteroid sized primordial black holes in the range of 3.5 × 10^−17 to 4 × 10^−12 solar masses (i.e. twelve to seventeen orders of magnitude smaller in mass than the Sun), which by definition cannot arise from stellar collapse. Non-detection of Hawking radiation (which is a net emission for primordial black holes up to about 10^-8 solar masses), and micro-lensing, has largely ruled out larger primordial black holes as a significant component of dark matter (if it exists). 

Also, while the paper frames its constraints in terms of primordial black holes, it would seem to apply to any dark matter candidate in that mass range, such as ordinary black holes and MACHOs (massive compact halo objects).

We present updated constraints on the abundance of primordial black holes (PBHs) dark matter from the high-redshift Lyman-α forest data from MIKE/HIRES experiments. Our analysis leverages an effective field theory (EFT) description of the 1D flux power spectrum, allowing us to analytically predict the Lyman-α fluctuations on quasi-linear scales from first principles. Our EFT-based likelihood enables robust inference across redshifts z = 4.2−5.4 and down to scales of 100 kpc, within previously unexplored regions of parameter space for this dataset. 

We derive new bounds on the PBH fraction with respect to the total dark matter fPBH, excluding populations with fPBH≳10^−3 for masses MPBH ∼ 10^4−10^16 M⊙. This offers the leading constraint for PBHs heavier than 10^9 M⊙ and highlights the Lyman-α forest as a uniquely sensitive probe of new physics models that modify the structure formation history of our universe.

Mikhail M. Ivanov, Sokratis Trifinopoulos, "Effective Field Theory Constraints on Primordial Black Holes from the High-Redshift Lyman-α Forest" arXiv:2508.04767 (August 6, 2025).

Another recent study (from August 11, 2025) reaches the same conclusion.

Additional Context

The Ordinary Matter Budget Of The Universe

Most of the ordinary matter in the universe is found in stars (about half) and the intergalactic/interstellar medium (mostly interstellar gas and dust) which is also about half, with planets and asteroids accounting for less than 1% of the total amount of ordinary mass in the universe. 

Stellar-mass black holes (formed from dying stars) account for not more than about 0.1% of the universe's ordinary matter, and supermassive black holes, found at the centers of galaxies, account for not more than about 0.01% of the universe's ordinary matter. 

Contributions to the mass-energy of the universe from photons and neutrinos are also very small (even though both kinds of particles are extremely numerous).

Planets, Asteroids, and Comets

Self-gravity forces planet-like objects of more than 0.5 x 10^21 kg (about one four billionth of the mass of the Sun) and more than 400 km in radius, to become approximately spherical, and this is the lower floor for dwarf planets, regular planets, and planet-sized moons. The mass of the Earth is about 3 x 10^-6 solar masses.

Objects smaller than this (but larger than dust or interstellar gas) tend to form non-spherical asteroids and comets, although some are approximately spherical due to random chance.

Star and Brown Dwarves

As an aside, anything other than a star or a black hole, can't have more than about 1.24% of the mass of the Sun (i.e. 13 Jupiter masses), because then gravity causes unstable nuclear fusion to commence in its core, turning it into a "sub-brown dwarf" although NASA conservatively assumes that planets could be as large as 30 Jupiter masses (about 2.86% of the mass of the Sun). In ideal conditions, a sub-brown dwarf can form at masses as low as one Jupiter mass (about 1/1024th of the mass of the Sun). Sub-brown dwarves and true brown dwarves, which range from 13 to 80 Jupiter masses (i.e. up to about 7.8% of the mass of the Sun) fill a liminal space between true planets with no gravity induced nuclear fusion and the smallest "main-sequence" stars. 

While brown dwarves are an order of magnitude or two heavier than large gas giant planets, like Jupiter and Saturn, they aren't much larger: "most brown dwarfs are slightly larger in volume than Jupiter (15–20%), but are still up to 80 times more massive due to greater density." Jupiter's radius is 11 times that of Earth, and the Sun's radius is 10 times that of Jupiter.

The theoretical maximum mass of a star is on the order of 200 solar masses. Of the billions and billions of stars that astronomers have observed, only 11 of them are potentially more than 150 solar masses, and only 5 of them have an upper end of their two sigma mass range (given the uncertainty of the mass measurement) above 200 solar masses. Only 2 stars have a best fit mass estimate above 200 solar masses, and realistically, given the uncertainty in these mass measurements (which is stated for one of the two and is not stated for the other), a mass of 200 solar masses of less is probably within the two sigma uncertainty range of the observation for both cases (particularly if one considers look elsewhere effects which are significant given the very large number of star masses measured).

The theoretically largest radius star is about 1700 times the radius of the Sun (by comparison, the orbit of Saturn is about 2,048 times the radius of the Sun). The largest radius star ever observed has a radius of 1530 ± 370 times the radius of the Sun.

Thus, any compact object with a mass of more than about 2 * 10^2 solar masses, or a radius more than about 1700 times the radius of the Sun (the Sun has a radius of about 700,000 km) is a supermassive black hole.  

Black Holes

An ordinary stellar collapse black hole has a minimum mass which is more than two times the mass of the Sun, but this minimum mass is a bit under three times the mass of the Sun. This mass, in the non-spinning case is called the Tolman-Oppenheimer-Volkoff limit.  In theory, this threshold mass may vary modestly based upon the spin of the neutron star. The mass limit is 18%-20% higher for a very rapidly spinning neutron star that is on the brink of becoming a black hole. A stellar mass black hole has an event horizon radius  (i.e. Schwarzschild radius radius) of about 6-9 km to 300 km.

The maximum density of anything ever observed in astronomy or high energy physics or nuclear physics is a neutron star/black hole right at the high end of the Tolman-Oppenheimer-Volkoff limit.

Pinning down the exact threshold more precisely is a matter of ongoing astronomy research. The least massive object definitively classified as a black hole has a mass of 3.04 ± 0.06 solar masses. A handful of observations of objects close to the limit have suggested a limit somewhere on the order of 2.01 to 2.9 solar masses.

Between stellar mass black holes (many of which have been indirectly observed) and supermassive black holes at the core of galaxies (many of which have been indirectly observed) are intermediate-mass black holes, which were first observed with gravitational wave telescopes:

An intermediate-mass black hole (IMBH) is a class of black hole with mass in the range of one hundred to one hundred thousand (10^2–10^5) solar masses: significantly higher than stellar black holes but lower than the hundred thousand to more than one billion (10^5–10^9) solar mass supermassive black holes.

An intermediate-mass black hole has an event horizon radius of 300 km to 300,000 km (which is smaller than the radius of the Sun). 

In theory, it would have been possible shortly after the Big Bang and predominantly in the first second after the Big Bang, for matter to be dense enough to form a black hole with less mass than necessary to form an ordinary stellar collapse black hole (even though the density needed to form a black hole increases as the mass which collapses into a black hole gets smaller).  These hypothetical black holes are called primordial black holes. 

But no primordial black holes have ever been observed, despite the fact that they are predicted to emit intense Hawking radiation (a.k.a. Bekenstein-Hawking radiation after Jacob Bekenstein, who died at age 68 in 2015, and Stephen Hawking, who died at age 76 in 2018, who both proposed it) which has never been detected:

Depending on the model, primordial black holes could have initial masses ranging from 10^−8 kg (the so-called Planck relics) to more than thousands of solar masses. However, primordial black holes originally having masses lower than 10^12 kg would not have survived to the present due to Hawking radiation, which causes complete evaporation in a time much shorter than the age of the Universe. . . . Primordial black holes are also good candidates for being the seeds of the supermassive black holes at the center of massive galaxies, as well as of intermediate-mass black holes.

The smaller the black hole, the more rapidly it evaporates due to Hawking radiation. A primordial black hole which initially had the mass of the Sun (2 * 10^30 kg) would now have a mass of something on the order of 10^23 kg (about one 10,000,000th the mass of the Sun) due to Hawking radiation (although accretion of new matter could counteract Hawking radiation and slow down the rate at which a primordial black hole's mass declines).

A hypothetical stable mass primordial black hole has an event horizon radius of at least 24 meters. Evaporating primordial black holes would have a smaller event horizon radius. An asteroid sized black hole would have an event horizon radius of about 0.03 millimeters to 3 meters and would emit significant Hawking radiation.

For black holes formed by stellar mass collapse (about 3 solar masses) or more, the mass loss due to Hawking radiation would be almost completely offset by accretion of mass-energy from its absorption of cosmic background radiation alone, setting aside interstellar dust and other objects that could fall into the black hole. Specifically:

Since the universe contains the cosmic microwave background radiation, in order for the black hole to dissipate, the black hole must have a temperature greater than that of the present-day blackbody radiation of the universe of 2.7 K. The relationship between mass and temperature for Hawking radiation then implies the mass must be less than 0.8% of the mass of the Earth [i.e. about 2.4 * 10^-8 solar masses]. This in turn means any black hole that could dissipate cannot be one created by stellar collapse. Only primordial black holes might be created with this little mass.

The theoretical maximum size of a black hole (with maximal spin) is 2.7 x 10^11 solar masses, and the most massive black hole ever observed has an estimated mass of up to 1 x 10^11 solar masses. The largest theoretically possible black hole has an event horizon radius of about 800 billion (i.e. 800,000,000,000) km.

A Notable Life In Quantum Physics

Chien-Shiung Wu was one of the pioneers of quantum mechanics and high energy physics, and was a female Chinese physicists in an era where women still made up only a tiny percentage of scientists in the field. 

If something remembers you with a speech like this, one hundred and ten years after you were born, when you have long passed away, then you did something right in life.

In 1950, Chien-Shiung Wu and her student published a coincidence experiment on entangled photon pairs that were created in electron-positron annihilation. This experiment precisely verified the prediction of quantum electrodynamics. 

Additionally, it was also the first instance of a precisely controlled quantum entangled state of spatially separated particles, although Wu did not know about this at the time. 

In 1956, Wu initiated and led the so-called Wu experiment, which discovered parity nonconservation, becoming one of the greatest experiments of the 20th century. 

As Chen Ning Yang said, Wu's experiments were well known for their precision and accuracy. Experimental precision and accuracy manifested Wu's scientific spirit, which we investigate here in some detail. 

Yu Shi, "Scientific Spirit of Chien-Shiung Wu: From Quantum Entanglement to Parity Nonconservation" arXiv:2504.16978 (May 31, 2022) (This paper is the translated transcript of the speech the author made at the International Symposium Commemorating the 110th Anniversary of the Birth of Chien-Shiung Wu, on May 31, 2022 in Chinese. The above abstract is the translation of the original abstract of the speech.)

She earned her undergraduate degree in physics (which had a thesis requirement at the time) in China in 1934, prior to the Maoist Revolution, and earned a PhD working under a professor only three years older than her who had studied under Madame Curie, and under the first female PhD in Physics in China, who earned that degree at the University of Michigan (where I also earned my graduate degree). Wu earned her PhD at the University of California at Berkley in 1940 (thirty years before my father earned his PhD at Stanford).

Wu was admitted by the University of Michigan to study at her own expense, and was financially supported by her uncle. On her way to Michigan, Wu visited Berkeley, where she was so impressed, especially by Ernest O. Lawrence’s cyclotron, that she wanted to stay in Berkeley. The cyclotron had been invented by Lawrence, so it was an ideal place for studying physics. Another important factor that influenced Wu’s decision was that she cared a lot about gender equality, and there was gender discrimination at the University of Michigan. In addition, there were a lot of Chinese students at the University of Michigan at the time, and Wu didn’t want her socializing be dominated by fellow Chinese students. So she stayed in Berkeley. Her decision reflected her devotion to physics as a woman.

She then taught at Smith (from which my sister-in-law graduated), and then Princeton, and then she worked at Columbia University as part of the Manhattan Project. 

She was highly productive (publishing more than fifty papers in the early 1950s when a huge share of U.S. women were homemakers in the Baby Boom), and her early post-war research agenda involved the verification of Fermi’s theory of β decay.

Chien-Shiung Wu served as the President of the American Physical Society from 1975 to 1976.

James W. Cronin, who won the 1980 Nobel Prize for his discovery of charge conjugation-parity (CP) nonconservation, once said, “The great discovery of Chien-Shiung Wu started the golden age of particle physics.” 

She continued to publish through at least 1980, and died in February of 1997. The author of the paper had met her.

Quote Of The Day

This paper is both novel and correct, but the novel part is not correct and the correct part is not novel.

From a peer review of an academic journal article attributed to physicist Wolfgang Pauli.

The Nobel Prize In Chemistry In 2024

Commentators have noted the AI trend in both the physics and the chemistry awards this year. 

The Nobel Prize in Chemistry was awarded on Wednesday to three scientists for discoveries that show the potential of advanced technology, including artificial intelligence, to predict the shape of proteins, life’s chemical tools, and to invent new ones.

The laureates are: Demis Hassabis and John Jumper of Google DeepMind, who used A.I. to predict the structure of millions of proteins; and David Baker of the University of Washington, who used computer software to invent a new protein.

From the New York Times. 

This Year's Nobel Prizes In STEM

The Nobel Prize in Physics for 2024 was awarded to John J. Hopfield and Geoffrey E. Hinton for their work in using machine learning methods (specifically, neural networks, a form of artificial intelligence) to solve physics problems. 

Both my son and his girlfriend currently work in the AI industry (and my brother and my daughter both work in the larger IT industry), so this is highly relevant to me personally. The large language models (LLMs) used in my own industry, law, are getting dramatically better by the year, but are still not ready for prime time and are prone to making things up and reaching absurd conclusions.

The prize in Physiology or Medicine went to Victor Ambros and Gary Ruvkun for their discovery of microRNA, which helps determine how cells develop and function. 

The Nobel prize in chemistry will be awarded tomorrow.

A "No Hype" Science Journalism Stand-Out

Science journalism aimed at the educated (or not so educated) layman in the general public is prone to sensationalism and claims of new discoveries that aren't supported by the body text, or at least, aren't supported by the source and the general scientific community. But there are exceptions. 

One stand out is an article from Phys.org which is a source that often offends in this regard but doesn't this time. Its headline accurately states:

Theoretical physicists find Higgs boson does not seem to contain any harbingers of new physics

The headline conclusion, reached after twelve years of study since its discovery was announced on July 4, 2012, is familiar to readers of this blog, but deserves recognition for resisting sensationalism and restating the scientific consensus.  See, e.g., noting decays to a Z boson and a photon and here (summarizing the data to date). 

The article used as its touchstone has the following abstract and citation (and isn't itself, the headline suggests, a broad review article, and is instead one more mundane article confirming that the experimental study of the Higgs boson confirms the theoretical expectations for it):

We evaluate the top-bottom interference contribution to the fully inclusive Higgs production cross section at next-to-next-to-leading order in QCD. Although bottom-quark-mass effects are power suppressed, the accuracy of state-of-the-art theory predictions makes an exact determination of this effect indispensable. The total effect of the interference at 13 TeV is −1.99⁢(1)+0.30−0.15  pb, while the pure 𝒪⁡(𝛼4𝑠) correction is 0.43 pb. With this result, we address one of the leading theory uncertainties of the cross section.

Michał Czakon et al, "Top-Bottom Interference Contribution to Fully Inclusive Higgs Production", Physical Review Letters (2024). DOI: 10.1103/PhysRevLett.132.211902

As additional context, Peter Higgs after whom the Higgs boson  is named, died in April of this year.

There is actually a slight Higgs boson anomaly, that is barely statistically significant locally (2.2 sigma), which would probably lose its statistical significance after considering look elsewhere effects, involving lower than expected Higgs boson decays to fermions (but the expected number of decays to bosons).

There are also a couple of low significance resonance "bumps" that have been touted as possible additional electromagnetically neutral Higgs bosons that have not been confirmed, one a bit below the Higgs boson mass of about 125 GeV, at about 96 GeV, and one or two a bit above it. Even if these "bumps" were confirmed to be real particles, there is no a priori reason to have any  confidence that they have anything to do with the Higgs boson.

Peter Higgs Has Died

Peter Higgs, the theoretical physicist whose name graces the Higgs boson, died this week.

Newton's Reign

It is sometimes hard to realize how far Issac Newton was ahead of his time. He was born 381 years ago. His scientific contributions were mostly in the time period from 1664, when he was 20 years old, until 1707, when he was 63 years old.

Only 13 of the chemical elements had been discovered at the time (one more would be discovered before his death), and the periodic table of the elements was about two centuries in the future. The germ theory of disease and modern genetics were centuries away. A theory of evolution, even Lamarkian evolution, was more than a century away. The Industrial Revolution was still more than a century away. Electromagnetism and thermodynamics hadn't been worked out in his lifetime. Telescopes (he invented the first practical reflecting telescope) and printing presses were relatively recent inventions. They were still burning witches. Gunpowder had been known in Europe for about four hundred years in his lifetime, but was just starting to become decisive militarily in his lifetime. He lived through the brief interregnum called the Common wealth of England, Scotland and Ireland, during which the British Isles was a republic without a reigning monarch. 

Newtonian mechanics, Newtonian gravity, and Newton's observations about optics went unchallenged and unamended for about 250 years. Scientists and engineers still use them on a daily basis, despite knowing that general relativity, special relativity, and quantum mechanics limit the range of their applicability.

The laws of physics he invented are still taught in high school and freshman college level physics classes. He co-invented calculus, which is still taught in high school and freshman and sophomore level college classes (although the notation of the independent co-inventor of calculus, Leibniz, rather than his own clunky notation, is used today).

Not all parts of Newton's legacy were equally illustrious. He was also a Unitarian theologian and an alchemist, and devoted almost as much time in his life to those ultimately fruitless projects, as he did to science and mathematics. He was also a member of Parliament, ran the Royal Mint for many years, was knighted, and led the Royal Society for twenty-four years. He never married and is not reputed to have had any children.

This Year's Nobel Prize In Physics

The 2023 Nobel Prize in physics has been awarded to a team of scientists who created a ground-breaking technique using lasers to understand the extremely rapid movements of electrons, which were previously thought impossible to follow.

Pierre Agostini, Ferenc Krausz and Anne L’Huillier “demonstrated a way to create extremely short pulses of light that can be used to measure the rapid processes in which electrons move or change energy,” the Nobel committee said when the prize was announced in Stockholm on Tuesday.

From CNN.

Usually, the Nobel Prize in Physics goes to someone who made a major theoretical advance. This year, however, the prize went to winners who developed a new experimental measurement technique.

This is fair. Experimentalists deserve their day in the sun and are absolutely critical to scientific advances in physics which are often under appreciated.

I wonder, however, if this choice doesn't also reflect ambivalence about which paths in the theoretical development of physics by physicists who are still alive and haven't yet received the prize, will turn out to be the right ones.

It Was Simple Before It Got Complicated

 

These guys, combined, left us with a pretty simple explanation of what the stuff in the Universe is made out of that remains perfectly adequate for a great many purposes, when combined with Newtonian gravity and mechanic's and Maxwell's equations of electromagnetism.

Almost immediately afterwards, however, we discovered quantum mechanics, neutrinos, quarks, gluons, weak force bosons, muons, tau leptons, the Higgs boson, photons, the strong force, the weak force, Special Relativity, and General Relativity, dark matter phenomena, and dark energy phenomena which made everything complicated again. 

The timing doesn't line up perfectly:

The discovery of the neutron and its properties was central to the extraordinary developments in atomic physics in the first half of the 20th century. Early in the century, Ernest Rutherford developed a crude model of the atom, based on the gold foil experiment of Hans Geiger and Ernest Marsden. In this model, atoms had their mass and positive electric charge concentrated in a very small nucleus. By 1920, isotopes of chemical elements had been discovered, the atomic masses had been determined to be (approximately) integer multiples of the mass of the hydrogen atom, and the atomic number had been identified as the charge on the nucleus. Throughout the 1920s, the nucleus was viewed as composed of combinations of protons and electrons, the two elementary particles known at the time, but that model presented several experimental and theoretical contradictions.

The essential nature of the atomic nucleus was established with the discovery of the neutron by James Chadwick in 1932 and the determination that it was a new elementary particle, distinct from the proton.

The uncharged neutron was immediately exploited as a new means to probe nuclear structure, leading to such discoveries as the creation of new radioactive elements by neutron irradiation (1934) and the fission of uranium atoms by neutrons (1938). The discovery of fission led to the creation of both nuclear power and nuclear weapons by the end of World War II. Both the proton and the neutron were presumed to be elementary particles until the 1960s, when they were determined to be composite particles built from quarks.

Newtonian mechanics and gravity (and calculus) all date to the late 1600s. 

Maxwell's equations for electromagnetism were published by 1862. Radioactivity, that would later be explained by the strong force and the weak force, had been discovered in the late 1800s.

Special Relativity (1905) (which is implicitly a part of Maxwell's equations), General Relativity (1915), and rudimentary quantum mechanics (reasonably well developed by the mid-1920s) were already in place before the neutron was discovered. 

Muons were discovered in 1936 although their place in the overall picture wasn't well understood at the time. 

Neutrinos were proposed in 1930, supported by evidence from beta decay in 1934, indirectly observed with physical evidence in 1938, and were first directly observed in 1956. 

The tau lepton was suspected in 1960 but wasn't confirmed until experiments done from 1974-1977.

Physics Needs Better Literature Reviews

One of my favorite physicists, Stacy McGaugh, reacting to a tweet expressing the same opinion by another of my favorite physicists, Sabine Hossenfelder, bemoans a cultural and institutional problem with the fundamental physics community that I agree is a serious one. 

What is it?

Physicists routinely publish papers that fail to review the literature sufficiently to identify the fact that previous published work already rules out, disproves, or contradicts the hypotheses that they are advancing in their papers.

It is a standard and almost universal practice that pretty much every thesis, dissertation, and published physics paper (other than a very short letter preliminarily reporting a very narrow measurement or result before a full length analysis of the results can be published) contains some review of the literature that brings the reader to the point of scientific knowledge where the matters being addressed by the authors in the new thesis, dissertation, or paper begins.

But, in many cases, this literature review is half-hearted and perfunctory, and misses key prior work relevant to the new paper.

For example, one of my pet peeves is when a paper says that their proposal is "well motivated" by concepts developed decades earlier that have later been found to be deeply flawed.

This isn't a "mortal sin". The physics literature is vast and it grows every week. Not everyone in the discipline can devote the time that I do to reading every abstract in a whole range of related fundamental physics categories every day when it comes out on arXiv. And, there are multiple ways of looking at a problem that can make identifying relevant papers challenging (the same issue comes up in doing patent and trademark searches, or searching for precedents related to a legal issue).

But, if you are going to be advancing a new hypothesis in this field, you really should do a proper literature review (and more generally, you should really know the literature relevant to your work from multiple perspectives) before advancing theories that are contradicted by other observational evidence or theoretical considerations that you don't mention or engage with in your paper.

You don't have to agree with everything else that has ever been published. Sometimes previously published papers are incorrect and you are right. But when that happens, rather than ignoring what previously published papers have to say, you really should engage with prior contradictory papers and explain why you think that their observations or analysis is flawed or inapplicable, and thus doesn't actually contradict your work.

You don't necessarily have to spell out the contradictions or flaws of the prior work in full in every new paper in a series of papers developing an idea. It is sufficient to do it once in your first paper identifying what you believe is a flaw in prior work and then to cite that that discussion, incorporating it by reference and with a brief mention, in later papers. But that is very different from ignoring contradictory prior work entirely.

If the authors of physics papers did more diligent and comprehensive literature reviews (and peer reviewers did a better job of insisting on better quality reviews of the literature which would catch both many innocent omissions and many cases where prior contradictory work is willfully ignored), the quality of the papers that did get published would be greater. This is because a lot of speculative garbage papers that ignore known insurmountable obstacles to their work would be dropped before they were presented.

Another Supposed Hint Of BSM Physics That Isn't One

Like every arguable experimental anomaly these days, the large number of high energy photons from GRB 221009A observed by LHAASO has given rise to many ambulance chasing papers purporting to explain these observations with "new physics" (which I do not dignify with citations at this blog). 

But, as this paper explains, these astronomy observations can be explained without physics beyond the core theory of the Standard Model and General Relativity. These results are at most, a slightly more than two sigma statistical fluke in circumstances where the reduction for look elsewhere effects needs to be significant.

Papers like this one that work hard to find a plausible explanation for seeming anomalies with well-established and proven "old physics" should be encouraged and should weigh far more heavily in hiring and promotions than ambulance chasing papers (although the poor English grammar in the title written by non-native English speakers should be remedied prior to publication).

It is reported that the Large High Altitude Air Shower Observatory (LHAASO) observed thousands of very-high-energy photons up to ∼18 TeV from GRB 221009A. We study the survival rate of these photons by considering the fact that they are absorbed by the extragalactic background light. 

By performing a set of 10^6 Monte-Carlo simulations, we explore the parameter space allowed by current observations and find that the probability of predicting that LHAASO observes at least one photons of 18 TeV from GRB 221009A within 2000 seconds is 4-5%. 

Hence, it is still possible for the standard physics to interpret LHAASO's observation in the energy range of several TeV. Our method can be straightforwardly generalized to study more data sets of LHAASO and other experiments in the future.

Zhi-Chao Zhao, Yong Zhou, Sai Wang, "Standard physics is still capable to interpret ∼18 TeV photons from GRB~221009A" arXiv:2210.10778 (October 16, 2022).

The 2022 Nobel Prize In Physics

This year's Nobel prize in Physics was awarded to three physicists who, independently and sequentially, experimentally confirmed that quantum entanglement was a real phenomena that worked in practice the way that quantum theory predicted that it would.

Émilie du Châtelet

She was featured in today's Google doodle.

Gabrielle Émilie Le Tonnelier de Breteuil, Marquise du Châtelet (French pronunciation: [emili dy ʃɑtlɛ] (listen); 17 December 1706–10 September 1749) was a French natural philosopher and mathematician during the early 1730s until her death due to complications during childbirth in 1749. Her most recognized achievement is her translation of and commentary on Isaac Newton's 1687 book Principia containing basic laws of physics. The translation, published posthumously in 1756, is still considered the standard French translation today. Her commentary includes a contribution to Newtonian mechanics—the postulate of an additional conservation law for total energy, of which kinetic energy of motion is one element. This led to her conceptualization of energy as such, and to derive its quantitative relationships to the mass and velocity of an object.

Her philosophical magnum opus, Institutions de Physique (Paris, 1740, first edition), or Foundations of Physics, circulated widely, generated heated debates, and was republished and translated into several other languages within two years of its original publication. She participated in the famous vis viva debate, concerning the best way to measure the force of a body and the best means of thinking about conservation principles. Posthumously, her ideas were heavily represented in the most famous text of the French Enlightenment, the Encyclopédie of Denis Diderot and Jean le Rond d'Alembert, first published shortly after du Châtelet's death. Numerous biographies, books and plays have been written about her life and work in the two centuries since her death. In the early 21st century, her life and ideas have generated renewed interest.

Émilie du Châtelet had, over many years, a relationship with the writer and philosopher Voltaire.

From Wikipedia. 

Go read the biography portion of the linked entry. Her life was quite remarkable. For example, "by the age of twelve she was fluent in Latin, Italian, Greek and German; she was later to publish translations into French of Greek and Latin plays and philosophy. She received education in mathematics, literature, and science. Du Châtelet also liked to dance, was a passable performer on the harpsichord, sang opera, and was an amateur actress. As a teenager, short of money for books, she used her mathematical skills to devise highly successful strategies for gambling."

Her life is also a reminder of the reality that in the 18th century even the scientifically minded nobility (her parents were minor nobles and part of the French King's court, her husband was a high ranking noble, and later in life she had affairs first with Voltaire, and then with a leading French poet) was not free of widespread infant and child and maternal mortality. Her experience in this regard was the norm, and not unusually tragic (see also, e.g., Euler).

Two of her five brothers died in childhood and two more died young. 

She gave birth four times. Her third and fourth children died as infants and she died giving birth to her fourth child at age forty-two.

Also:

On 12 June 1725, she married the Marquis Florent-Claude du Chastellet-Lomont. Her marriage conferred the title of Marquise du Chastellet. Like many marriages among the nobility, theirs was arranged. As a wedding gift, the husband was made governor of Semur-en-Auxois in Burgundy by his father; the recently married couple moved there at the end of September 1725. Du Châtelet was eighteen at the time, her husband thirty-four.

About Newton

Everyone remembers Newton for his contributions to physics. 

But he made much of his fortune as the director of London's mint, making coins, and investing in businesses, after he got sick of being a professor at Cambridge, where he felt tormented as a Unitarian in a Trinitarian institution.

Quote of the Day

Genzel and Ghez led two teams that peered into the center of our galaxy. By carefully measuring the way stars moved deep in the core, they figured out something we now teach children: that our beloved Milky Way has a dark and chewy center, an enormous black hole around which everything else revolves.

From 4gravitons writing about two of the Nobel Prize in Physics award winners in 2020.

Nobel Prizes 2020 (Chemistry and Physics and Medicine)

The Nobel Prize in Physics was awarded for major discoveries in black hole physics that are now mostly old news.  Past awards are listed here.

Penrose (who is still a leader in theoretical general relativity) won half for drawing the theoretical conclusion that black holes existed (subsequently born out by observations) from the equations of GR in 1965. Einstein didn't think that this conclusion could possibly be correct. Stephen Hawking was a collaborator with Roger Penrose on this work, but you have to be alive to qualify for the Nobel Prize and Hawking recently died.

Genzel and Ghez won for finding the black hole at the center of the Milky Way in the early 1990s.

The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics 2020 with one half to Roger Penrose, University of Oxford, UK “for the discovery that black hole formation is a robust prediction of the general theory of relativity” and the other half jointly to Reinhard Genzel, Max Planck Institute for Extraterrestrial Physics, Garching, Germany and University of California, Berkeley, USA and Andrea Ghez, University of California, Los Angeles, USA “for the discovery of a supermassive compact object at the centre of our galaxy”.

Roger Penrose used ingenious mathematical methods in his proof that black holes are a direct consequence of Albert Einstein’s general theory of relativity. Einstein did not himself believe that black holes really exist, these super-heavyweight monsters that capture everything that enters them. Nothing can escape, not even light.

In January 1965, ten years after Einstein’s death, Roger Penrose proved that black holes really can form and described them in detail; at their heart, black holes hide a singularity in which all the known laws of nature cease. His groundbreaking article is still regarded as the most important contribution to the general theory of relativity since Einstein.

Reinhard Genzel and Andrea Ghez each lead a group of astronomers that, since the early 1990s, has focused on a region called Sagittarius A* at the centre of our galaxy. The orbits of the brightest stars closest to the middle of the Milky Way have been mapped with increasing precision. The measurements of these two groups agree, with both finding an extremely heavy, invisible object that pulls on the jumble of stars, causing them to rush around at dizzying speeds. Around four million solar masses are packed together in a region no larger than our solar system.

Using the world’s largest telescopes, Genzel and Ghez developed methods to see through the huge clouds of interstellar gas and dust to the centre of the Milky Way. Stretching the limits of technology, they refined new techniques to compensate for distortions caused by the Earth’s atmosphere, building unique instruments and committing themselves to long-term research. Their pioneering work has given us the most convincing evidence yet of a supermassive black hole at the centre of the Milky Way.

The Nobel Prize in Chemistry went to two women who, working together, developed CRISPR, the first and most important true gene editing technique, in 2011-2012. Past awards are listed here.

The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Chemistry 2020 to Emmanuelle Charpentier Max Planck Unit for the Science of Pathogens, Berlin, Germany and Jennifer A. Doudna University of California, Berkeley, USA “for the development of a method for genome editing”

Emmanuelle Charpentier and Jennifer A. Doudna have discovered one of gene technology’s sharpest tools: the CRISPR/Cas9 genetic scissors. Using these, researchers can change the DNA of animals, plants and microorganisms with extremely high precision. This technology has had a revolutionary impact on the life sciences, is contributing to new cancer therapies and may make the dream of curing inherited diseases come true.

Researchers need to modify genes in cells if they are to find out about life’s inner workings. This used to be time-consuming, difficult and sometimes impossible work. Using the CRISPR/Cas9 genetic scissors, it is now possible to change the code of life over the course of a few weeks.

“There is enormous power in this genetic tool, which affects us all. It has not only revolutionised basic science, but also resulted in innovative crops and will lead to ground-breaking new medical treatments,” says Claes Gustafsson, chair of the Nobel Committee for Chemistry.

As so often in science, the discovery of these genetic scissors was unexpected. During Emmanuelle Charpentier’s studies of Streptococcus pyogenes, one of the bacteria that cause the most harm to humanity, she discovered a previously unknown molecule, tracrRNA. Her work showed that tracrRNA is part of bacteria’s ancient immune system, CRISPR/Cas, that disarms viruses by cleaving their DNA.

Charpentier published her discovery in 2011. The same year, she initiated a collaboration with Jennifer Doudna, an experienced biochemist with vast knowledge of RNA. Together, they succeeded in recreating the bacteria’s genetic scissors in a test tube and simplifying the scissors’ molecular components so they were easier to use.

In an epoch-making experiment, they then reprogrammed the genetic scissors. In their natural form, the scissors recognise DNA from viruses, but Charpentier and Doudna proved that they could be controlled so that they can cut any DNA molecule at a predetermined site. Where the DNA is cut it is then easy to rewrite the code of life.

Since Charpentier and Doudna discovered the CRISPR/Cas9 genetic scissors in 2012 their use has exploded. This tool has contributed to many important discoveries in basic research, and plant researchers have been able to develop crops that withstand mould, pests and drought. In medicine, clinical trials of new cancer therapies are underway, and the dream of being able to cure inherited diseases is about to come true. These genetic scissors have taken the life sciences into a new epoch and, in many ways, are bringing the greatest benefit to humankind.

The Nobel Prize in Medicine was awarded for discovering the hepatitis C virus.

Drs. Harvey J. Alter, Michael Houghton and Charles M. Rice on Monday received the prize for their discovery of the hepatitis C virus. The Nobel committee said the three scientists had “made possible blood tests and new medicines that have saved millions of lives.”

Remembering A Real Scientific Hero

Four years ago [as of August 18, 2019], Syrian archaeologist Khaled Al-Asaad was murdered by Daesh after refusing to give away the location of hidden artefacts in Palmyra. He gave his life for the heritage he had dedicated his life to, in defiance of brutality, extremism, and authoritarianism.

From here.

Carl Friedrich Gauss

Today's Google doodle is of Johann Carl Friedrich Gauß a.k.a. Carl Friedrich Gauss on the 241st anniversary of his birth, who is best known for his contributions to mathematics and physics. 

He lived from 1777 to 1855, yet he is still a "household name". His name is the source of the term "Gaussian" to refer to a "normal" distribution in statistics; he was the first to prove the fundamental theorem of algebra; his gravitational constant, k, which is the positive square root of Newton's constant G, was still in use as an official physical constant until 2012 at very nearly the value he determined for it; and his calculations were used to rediscover dwarf planet Ceres. 

The year 1796 [when he was 19 years old] was most productive for both Gauss and number theory. He discovered a construction of the heptadecagon on 30 March. He further advanced modular arithmetic, greatly simplifying manipulations in number theory. On 8 April he became the first to prove the quadratic reciprocity law. This remarkably general law allows mathematicians to determine the solvability of any quadratic equation in modular arithmetic. The prime number theorem, conjectured on 31 May, gives a good understanding of how the prime numbers are distributed among the integers. 

Gauss also discovered that every positive integer is representable as a sum of at most three triangular numbers on 10 July and then jotted down in his diary the note: "ΕΥΡΗΚΑ! num = Δ + Δ' + Δ". On 1 October he published a result on the number of solutions of polynomials with coefficients in finite fields, which 150 years later led to the Weil conjectures.

He was a monarchist and a faithful Lutheran who never lived to see Germany as a unified country. He spent most of his life as an royal astronomer.

His first wife and love of his life life died in connection with the birth of their third child who died as an infant. Shortly thereafter, he married his late wife's best friend and they had three more children over the next twenty years after which she died, but he spent his entire life after the death of his first wife and his infant child in mourning.

He was one of the great mathematical geniuses of all time, but deliberately concealed from the world the methods by which he reached his final crystalized conclusions and declined to publish a large share of his findings and discoveries which he felt were inferior to his greatest accomplishments. He had few students, but was a mentor to Bernhard Riemann, whose non-Euclidian geometry was pivotal to the formulation of General Relativity, and a correspondent of Bessel (after whom "Bessel functions" are named) for whom he secured an honorary degree.

Lubos Still Addicted To Pseudo-Science Of Naturalness

Most physicists have (or should have) woken up to the idea that "naturalness" is a fundamentally flawed concept with no validity in generating hypotheses that simply amounts to numerology.

But, Lubos Motl clings to this absurd and presumptuous notion that the universe ought to conform to his preconceptions, even though he should know better.

Sabine's most excellent rant on this subject which I wholeheartedly endorse, is here.